Self-locking tube protector and deflector block for boiler tubes

ABSTRACT

Self-locking tube protectors and deflector blocks are provided for protecting boiler tubes in the path of fuel injected between upper and lower fuel inlet plates having studs aligned with the tubes on the fuel inlet side thereof. A pair of cooperating tube protector sections are shaped at adjacent one ends thereof to substantially encircle a tube when installed. The inner surfaces of the protector sections have cooperating grooves to fit a stud, and tongue and groove means for locking the inlet ends of the sections together when installed. A deflector block fits over the tube ends of the protector sections and overlaps the crack between the ends. Mating tapered ear and groove joint sections are provided at the tube ends of the protector sections and on the deflector block for clamping the sections firmly against the tube when the block is installed. The deflector block has a recess on one lateral side and a tongue on the other predetermined to overlap the tongue and recess of deflector blocks on adjacent tubes when installed.

United States Patent 1 a 1 97,416 Lawson Mar. 19, 1974 SELF-LOCKING TUBE PROTECTOR AND [57] ABSTRACT DEFLECTOR BLOCK FOR BOILER TUBES Self-locking tube protectors and deflector blocks are [76] Inventor: Gl H, Law 701 E, M i S provided for protecting boiler tubes in the path of fuel Madison, 1nd. 47250 injected between upper and lower fuel inlet plates having studs aligned with the tubes on the fuel inlet [22] 1973 side thereof. A pair of cooperating tube protector sec- 21 A 1. No.; 349 749 tions are shaped at adjacent one ends thereof to substantially encircle a tube when installed. The inner surfaces of the protector sections have cooperating [52] 110/28 1 10/28 4 grooves to fit a stud, and tongue and groove means for "-R B locking the inlet ends of the sections togetherwhen installed. A deflector block fits over the tube ends of the protector sections and overlaps the crack between the ends. Mating tapered ear and groove joint sections [56] References Cited are provided at the tube ends of the protector sections UNITED STATES PATENTS and on the deflector block for clamping the sections 2.055.722 9/1936 Hardgrove 122/235 firmly against the tube when the block is installed. The

2.397.793 4/19 6 Leach 122/23 X deflector block has a recess on one lateral side and a 2.636.483 Bailey et 21! X tongue on the other predetermined to verlap the tongue and recess of deflector blocks on adjacent tubes when installed.

110/28 R, 28 A, 98 R Primary ExaminerKenneth W. Sprague Attorney. Agent, or Firm-Pennie & Edmonds 8 Claims, 5 Drawing Figures llllll SELF-LOCKING TUBE PROTECTOR AND DEFLECTOR BLOCK FOR BOILER TUBES BACKGROUND OF THE INVENTION Tube protectors and deflector blocks are used in the burner area of boilers where the fuel is blown by the water wall tubes. Commonly fuel is injected between upper and lower fuel inlet plates having studs aligned with the tubes on the fuel inlet side thereof. The tube protectors extend from top to bottom of the inlet plates and their sides are commonly tapered in a generally air foil configuration to facilitate passage of fuel thereby. Deflector blocks are mounted on the furnace sides of the tubes to direct fuel upwards and downwards and to protect the furnace sides of thetubes. The tube protectors protect the tubes from erosion, which is particularly important when pulverized coal is used as the fuel.

Tube protectors and deflector blocks are known which are made in two sections designed to fit around approximately half the circumference of a tube, with grooves fitting around the respective stud. The two sections are inserted from the inside of the boiler and then bolted together in place. The deflector block fits around a quarter of the remaining circumference of the tube and a quarter of the adjacent tube. A long securing bolt extends from the central portion of the deflector block and between two adjacent tube protectors to a threaded hole in a plate'in the fuel vent.

This prior art arrangement is subject to a number of disadvantages. Protection of the tube is incomplete because of the cracks between the tube protector sections and the deflector blocks and between deflector blocks, so that tube erosion can occur and cause leaks. The securing bolts also cause problems since they tend to erode as well as restrict the flow of fuel. Erosion of a bolt may cause the loss of the deflector block secured thereby, thus leaving part of the furnace side of tubes exposed.

fit a stud aligned with the tube so as to position the protector properly. Tongue and groove means is provided toward the other ends of the sections for locking those ends together when installed. The: sections may have inwardly tapered side walls and vertical dimensions predetermined to substantially contact the upper and lower fuel inlet plates when installed.

The deflector block is shaped to fit over the tube ends of the protector sections and overlaps the crack between the ends. Matingtapered ear and groove joint sections are provided at the tube ends of the protector sections and on the deflector block for clamping the sections firmly against the tube when the block is installed. Preferably the tapered ear and groove sections are wider at the bottom than at the top thereof, and the ear sections are integral with the tube protector sections and the grooves are formed in the deflector block.

To install, the two protector sections are inserted from inside the boiler on each side of the tube and aligned stud, the tongue of one section is inserted in the groove of the other, and the tube brought together around the tube. The deflector block is then slipped over the tube ends of the protector sections and driven into place to hold the assembly firmly on the tube and aligned stud. Thus the three parts are self-locking and easily installed, and no retaining bolt is required. Also the tube is completely encircled,.since the crack between the ends of the protector sections is covered by Accordingly, with this prior arrangement considerv ablemaintenance is required to keep the boiler in operation. For example, in one plant having six boilers, over twelve hundred deflector blocks and tube protectors were employed, and over a period of several years the average number replaced each year was approximately the total number employed. This is expensive not only because of the material costs, but also because of the labor costs involved in deslagging the furnace to obtain access to the protectors and deflector blocks, repairing defective tubes, and installing new protectors and deflector blocks. Further, since the boiler must be shut down, the length and frequency of outages is a significant factor. 1

The present invention provides a self-locking tube protector and deflector block which more completely protects the tube, is more easily and quickly installable, and eliminates the need for long securing bolts. Also, a longer average life span may be obtained.

SUMMARY OF THE INVENTION A pair of cooperating tube protector sections are shaped at adjacent one ends thereof to substantially encircle a boiler tube in contact therewith when installed. The protector sections extend toward the fuel inlet side of the tube when installed, and have cooperating grooves on the inner surfaces thereof predetermined to the deflector block.

Advantageously the deflector block has a recess on one lateral side and a tongue on the opposite side predetermined to overlap the tongue and recess of deflector blocks on adjacent tubes in. mating relationship when installed, thereby preventing erosion between blocks.

Further features will in part be pointed out in the following description of a specific embodiment of the invention, and in part be understood therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-section through the burner area between boiler tubes;

FIG. 2 is a view of the deflector blocks from the interior of the furnace;

FIG. 3 shows cross-sections of the assembled tube protectors and deflector blocks taken along the line DESCRIPTION OF THE SPECIFIC EMBODIMENT Referring to FIGS. 1 and 2, a portion of the wall of a boiler is shown having upper and lower fuel inlet plates 10, 11 between which fuel is injected into the furnace area 12. As specifically illustrated the fuel is pulverized coal and plates 10, 11 may be considered a coal vent having a rectangular opening to the furnace area. In the path of the fuel are boiler tubes 13. Vertical studs are attached to plates 10, 11 in alignment with tubes 13 and one stud is shown at 14. It is retained in place by washers and nuts as shown.

Each tube 13 is provided with a tube protector 15 and deflector block 16 which will be described more fully hereinafter. The tube protector 15 extends toward the fuel inlet side of tube 13 in substantial contact with plates and 11 and fuel flows between adjacent tube protectors and then over and under the deflector blocks, as indicated at 17. To this end, plates 10 and 11 terminate part way across the tube 13, as shown at 10 and 11.

The structure described so far is known in the art, except for the design of the tube protector and deflector block, and may take various forms to which the tube protector and deflector block may be adapted. Many structural details have been omitted since they are unnecessary for an understanding of the present invention.

Referring now to FIGS. 35, the tube protector generally designated as 15 is formed in two sections 21, 22. Respective adjacent ends 21', 22 are shaped to substantially encircle tube 13 in contact therewith when installed as shown in FIG. 3, and here take the form of half cylinders on their inner surfaces. The two sections extend toward the fuel inlet side of tube 13, the direction of fuel flow being indicated by arrow 23, and have cooperating grooves 24, 24' on the inner surfaces thereof predetermined to fit a stud 14 in positioning relationship when installed. Tongue and groove means 44, 45 are provided for locking the fuel inlet ends of the sections together, when installed. A slight clearance may be required, as shown, to allow for manufacturing tolerances and ease of insertion.

As will be apparent, the separate sections 21, 22 can readily be inserted on opposite sides of a given tube 13 from the furnace side 12 thereof, the tongue inserted in the groove, and the ends 21, 22' brought together around the tub 13.

A deflector block 26 has an inner surface 27 shaped to fit over the ends 21', 22' of the protector sections and overlap the crack28 between the ends. Mating tapered ear and groove joint sections are provided at the ends of the protector sections and on the deflector block for clamping the protector sections firmly against the tube when the block is installed. Thus ends 21', 22' are'provided with tapered ears 29, 29' or dove-tails, as best seen in FIG. 4, and the deflector block is provided with tapered grooves 31,31 as best seen in FIG. 5. Advantageously the tapered ears and grooves are wider at the bottom than at the top, so that the deflector block can be installed from above the protector sections and driven downward into place.

As will be observed, when the deflector block is in place, the tube 13 is completely encircled and the crack 28 is covered, thereby reducing the erosion that can take place and fully protecting the tube. It will be understood that although it would be desirable for the protector sections to abut when in place, some tolerance is necessary in practice to insure a tight clamping of the sections around the tube.

The deflector block 26 is dimensioned to extend laterally of a tube 13 on each side thereof when installed,

and has a recess 32 on one lateral side and a tongue 33 on the other. When installed, the tongue of one block mates with the recess of the adjacent block on that side, and the recess mates with the tongue of the block on the other side. Thus the overlapping of tongue and recess guards against erosion between the blocks.

The side walls of the protector sections 21, 22 may be inwardly tapered in generally air foil configuration to allow fuel to flow thereby without unduly impairing fuel flow, as best seen in FIG. 3. The inner sides 34, 34'

of the deflector block may also be tapered to facilitate fuel flow above and below the block, as best seen in FIG. 1.

As will be understood, the two sections 21, 22 of the tube protectors and the deflector blocks are selflocking and easily installed, and no retaining bolts between the tubes are required.

When made of suitable material such as a nickel alloy, a relatively long life may be expected. When replacement is necessary, a considerable reduction in labor installation costs may be obtained as compared to present costs. Consequently, although the tube protector and deflector block may be somewhat more expensive than those presently available, a significant reduction in overall maintenance costs may be obtained, and the length and frequency of outages may be reduced.

1 claim: 1. A tube protector and deflector block for protecting boiler tubes in the path of fuel injected between upper and lower fuel inlet plates having studs aligned with said tubes on the fuel inlet side thereof, which comprises a. a pair of cooperating tube protector sections shaped at adjacent one ends thereof to substantially encircle a said tube in contact therewith when installed, I r

b. said protector sections extending toward the fuel inlet side of said tube when installed and having 00- operating grooves on the inner surfaces thereof predetermined to fit a said stub in positioning relationship when installed,

0. tongue and groove means toward the other ends of said sections for locking said other ends together when installed,

d. a deflector block shaped to fit over said one ends of the protector sections when installed and overlap the crack between said one ends,

e. and mating tapered ear and groove joint sections at respective one ends of the protector sections and on said deflector block for clamping said sections firmly against said tube when said block is installed.

2. Apparatus according to claim 1 in which said protector sections extending toward the fuel inlet side of a tube when installed have inwardly tapered side walls and vertical dimensions predetermined to substantially contact said upper and lower fuel inlet plates.

3. Apparatus according to claim 1 in which said tongue and groove means are positioned beyond said grooves on respective protector sections to lock together inwardly of said stud when installed.

4. Apparatus according to claim 1 in which said tapered ear and groove -joint sections are wider at the bottom than at the top thereof.

5. Apparatus according to claim 4 in which the tapered ears of said joint sections are integral with respective one ends of the tube protector sections and the tapered grooves are formed in said deflector block.

6. Apparatus according to claim 1 in which said deflector block is predetermined to extend laterally of a tube on each side thereof when installed and has a recess on one lateral side and a tongue on the other lateral side predetermined to overlap the tongue and recess of deflector blocks on adjacent tubes in mating relationship when installed.

7. Apparatus according to claim 1 in which said tongue and groove means are positioned beyond said grooves on respective protector sections to lock together inwardly of said stud when installed, the tapered ears of said joint sections are integral with respective one ends of the tube protector sections and the tapered grooves are formed in said deflector block, said tapered ears and grooves being wider at the bottom than at the top thereof, and said deflector block is predetermined to extend laterally of a tube on each side thereof when contact said upper and lower fuel inlet plates. 

1. A tube protector and deflector block for protecting boiler tubes in the path of fuel injected between upper and lower fuel inlet plates having studs aligned with said tubes on the fuel inlet side thereof, which comprises a. a pair of cooperating tube protector sections shaped at adjacent one ends thereof to substantially encircle a said tube in contact therewith when installed, b. said protector sections extending toward the fuel inlet side of said tube when installed and having cooperating grooves on the inner surfaces thereof predetermined to fit a said stub in positioning relationship when installed, c. tongue and groove means toward the other ends of said sections for locking said other ends together when installed, d. a deflector block shaped to fit over said one ends of the protector sections when installed and overlap the crack between said one ends, e. and mating tapered ear and groove joint sections at respective one ends of the protector sections and on said deflector block for clamping said sections firmly against said tube when said block is installed.
 2. Apparatus according to claim 1 in which said protector sections extending toward the fuel inlet side of a tube when installed have inwardly tapered side walls and vertical dimensions predetermined to substantially contact said upper and lower fuel inlet plates.
 3. Apparatus according to claim 1 in which said tongue and groove means are positioned beyond said grooves on respective protector sections to lock together inwardly of said stud when installed.
 4. Apparatus according to claim 1 in which said tapered ear and groove joint sections are wider at the bottom than at the top thereof.
 5. Apparatus according to claim 4 in which the tapered ears of said joint sections are integral with respective one ends of the tube protector sections and the tapered grooves are formed in said deflector block.
 6. Apparatus according to claim 1 in which said deflector block is predetermined to extend laterally of a tube on each side thereof when installed and has a recess on one lateral side and a tongue on the other lateral side predetermined to overlap the tongue and recess of deflector blocks on adjacent tubes in mating relationship when installed.
 7. Apparatus according to claim 1 in which said tongue and groove means are positioned beyond said grooves on respective protector sections to lock together inwardly of said stud when installed, the tapered ears of said joint sections are integral with respective one ends of the tube protector sections and the tapered grooves are formed in said deflector block, said tapered ears and grooves being wider at the bottom than at the top thereof, and said deflector block is predetermined to extend laterally of a tube on each side thereof when installed and has a recess on one lateral side and a tongue on the other lateral side predetermined to overlap the tongue and recess of deflector blocks on adjacent tubes in mating relationship when installed.
 8. Apparatus according to claim 7 in which said protector sections extending toward the fuel inlet side of a tube when installed have inwardly tapered side walls and vertical dimensions predetermined to substantially contact said upper and lower fuel inlet plates. 